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Microstructural and thermal properties of coal measure sandstone subjected to high temperatures

Journal of Rock Mechanics and Geotechnical Engineering 2024年第8期16卷 2909-2921页

作者： Weijing Xiao Dongming Zhang Shujian Li mingyang wu School of Civil Engineering and Architecture East China Jiaotong UniversityNanchang330013China State Key Laboratory of Coal Mine Disaster Dynamics and Control Chongqing UniversityChongqing400044China Yunnan Phosphate Chemical Group Co. Ltd.Kunming650600China National Engineering and Technology Research Center for Development and Utilization of Phosphate Resources Kunming650600China State Key Laboratory of Geomechanics and Geotechnical Engineering Institute of Rock and Soil MechanicsChinese Academy of SciencesWuhan430071China

To study the microscopic structure,thermal and mechanical properties of sandstones under the influence of temperature,coal measure sandstones from Southwest China are adopted as the research object to carry out high-temperature tests at 25℃-1000℃.The microscopic images of sandstone after thermal treatment are obtained by means of polarizing microscopy and scanning electron microscopy(SEM).Based on thermogravimetric(TG)analysis and differential scanning calorimetric(DSC)analysis,the model function of coal measure sandstone is explored through thermal analysis kinetics(TAK)theory,and the kinetic parameters of thermal decomposition and the thermal decomposition reaction rate of rock are *** the uniaxial compression experiments,the stress‒strain curves and strength characteristics of sandstone under the influence of temperature are *** results show that the temperature has a significant effect on the microstructure,mineral composition and mechanical properties of *** particular,when the temperature exceeds 400℃,the thermal fracture phenomenon of rock is obvious,the activity of activated molecules is significantly enhanced,and the kinetic phenomenon of the thermal decomposition reaction of rock appears *** mechanical properties of rock are weakened under the influence of rock thermal fracture and mineral thermal *** research results can provide a reference for the analysis of surrounding rock stability and the control of disasters caused by thermal damage in areas such as underground coal gasification(UCG)channels and rock masses subjected to mine fires.

关键词： Rock mechanics Coal measure sandstone Micromorphology Thermal damage

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Experimental Research on the Surface Quality of Milling Contour Bevel Gears

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Chinese Journal of Mechanical Engineering 2023年第1期36卷 115-128页

作者： mingyang wu Jianyu Zhang Chunjie Ma Yali Zhang Yaonan Cheng School of Mechanical and Power Engineering Harbin University of Science and TechnologyHarbin150080China The Key Laboratory of National and Local United Engineering for“High-Efficiency Cutting and Tools” Harbin150080China

Contour bevel gears have the advantages of high coincidence,low noise and large bearing capacity,which are widely used in automobile manufacturing,shipbuilding and construction ***,when the surface quality is poor,the effective contact area between the gear mating surfaces decreases,affecting the stability of the fit and thus the transmission accuracy,so it is of great significance to optimize the surface quality of the contour bevel *** paper firstly analyzes the formation process of machined surface roughness of contour bevel gears on the basis of generating machining method,and dry milling experiments of contour bevel gears are conducted to analyze the effects of cutting speed and feed rate on the machined surface roughness and surface topography of the ***,the surface defects on the machined surface of the workpiece are studied by SEM,and the causes of the surface defects are analyzed by *** that,XRD is used to compare the microscopic grains of the machined surface and the substrate material for diffraction peak analysis,and the effect of cutting parameters on the microhardness of the workpiece machined surface is investigated by work hardening *** research results are of great significance for improving the machining accuracy of contour bevel gears,reducing friction losses and improving transmission efficiency.

关键词： Contour bevel gear Machined surface quality Surface roughness Surface defect Surface morphology

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Fusion network for small target detection based on YOLO and attention mechanism

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Optoelectronics Letters 2024年第6期20卷 372-378页

作者： XU Caie DONG Zhe ZHONG Shengyun CHEN Yijiang PAN Sishun wu mingyang School of Information and Electronic Engineering Zhejiang University of Science and TechnologyHangzhou 310012China Research Development Department Hangzhou Xinhe Data Technology Co.Ltd.Hangzhou 311202China College of Mechanical Engineering Zhejiang UniversityHangzhou 310013China

Target detection is an important task in computer vision research, and such an anomaly detection and the topic of small target detection task is more concerned. However, there are still some problems in this kind of researches, such as small target detection in complex environments is susceptible to background interference and poor detection results. To solve these issues, this study proposes a method which introduces the attention mechanism into the you only look once(YOLO) network. In addition, the amateur-produced mask dataset was created and experiments were conducted. The results showed that the detection effect of the proposed mothed is much better.

关键词： Fusion network for small target detection based on YOLO and attention mechanism

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Big Disaster from Small Watershed:Insights into the Failure and Disaster‑Causing Mechanism of a Debris Flow on 25 September 2021 in Tianquan,China

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International Journal of Disaster Risk Science 2024年第4期15卷 622-639页

作者： Runing Hou mingyang wu Zhi Li Ningsheng Chen Xiaohu Chen Taixin Peng Na Huang Key Laboratory of Mountain Hazards and Surface Processes Institute of Mountain Hazards and EnvironmentChinese Academy of SciencesChengdu 610041China School of Geosciences Yangtze UniversityWuhan 430100China Academy of Plateau Science and Sustainability Xining 810016China University of Chinese Academy of Sciences Beijing 100049China

The occurrence of debris flow events in small-scale watersheds with dense vegetation in mountainous areas that result in significant loss of life and missing individuals challenges our understanding and expertise in investigating and preventing these disasters. This has raised concerns about the occurrence of large debris flow disasters from small watersheds. This study focused on a catastrophic debris flow that took place in Longtou Gully(0.45 km^(2)) in Tianquan County, Ya'an City on 25 September 2021, which resulted in 14 deaths and missing individuals. Through comprehensive field investigations, highprecision remote sensing data analyses, and numerical simulations, we analyzed the triggering mechanisms and dynamic processes of this event. Our results indicate that the convergence hollow at the channel head exhibited higher hydraulic conditions during rainfall compared to gentle slopes and convex terrains, leading to the instability of colluvial soil due to the expansion of the saturated zone near the soil–bedrock interface. The entrainment of material eroded from the channel resulted in an approximately 4.7 times increase in volume, and the channel scarp with a height of about 200 m amplified the destructive power of the debris flow. We emphasize the need to take seriously the possibility of catastrophic debris flows in small-scale watersheds, with colluvial deposits in hollows at the channel head under vegetation cover that serve as precursor material sources, and the presence of channel scarps formed by changes in the incision rate of the main river, which is common in the small watershed on both sides. This study provides insights for risk assessment of debris flows in small-scale catchments with dense vegetation cover in mountainous areas, highlighting the importance of vigilance in addressing disasters in small-scale catchments, particularly in regions with increasing human–environment conflicts.

关键词： China Colluvial soil Low-frequency debris fows Risk reduction Topographic hollows

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Effects of magnetic field on electron power absorption in helicon fluid simulation

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Plasma Science and Technology 2021年第8期23卷 29-37页

作者： mingyang wu Chijie XIAO Yue LIU Xiaoyi YANG Xiaogang WANG Chang TAN Qi SUN State Key Laboratory of Nuclear Physics and Technology School of PhysicsFusion Simulation CenterPeking UniversityBeijing 100871People's Republic of China Key Laboratory of Materials Modification by Laser Ion and Electron Beams(Ministry of Education)School of PhysicsDalian University of TechnologyDalian 116024People's Republic of China Harbin Institute of Technology Harbin 150001People's Republic of China Shaanxi Key Laboratory of Plasma Physics and Applied Technology Xi'an 710100People's Republic of China Xi'an Aerospace Propulsion Institute Xi'an 710100People's Republic of China School of Physics Beijing Institute of TechnologyBeijing 100081People's Republic of China

In this study,a code,named Peking University Helicon Discharge(PHD),which can simulate helicon discharge processes under both a background magnetic field greater than 500 G and a pressure less than 1 Pa,is *** the code,two fluid equations are *** PHD simulations led to two important findings:(1)the temporal evolution of plasma density with the background magnetic field exhibits a second rapid increase(termed as the second density jump),similar to the transition of modes in helicon plasmas;(2)in the presence of a magnetic field,the peak positions of electron power absorption appeared near the central axis,unlike in the case of no magnetic *** results may lead to an enhanced understanding of the discharge mechanism.

关键词： helicon plasma discharge process numerical simulation

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Relationship of mode transitions and standing waves in helicon plasmas

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Plasma Science and Technology 2022年第5期24卷 80-86页

作者： mingyang wu Chijie XIAO Xiaogang WANG Yue LIU Min XU Chang TAN Tianchao XU Xiuming YU Renchuan HE Andong XU State Key Laboratory of Nuclear Physics and Technology School of PhysicsFusion Simulation CenterPeking UniversityBeijing 100871People’s Republic of China Department of Physics Institute of Space Environment and Matter ScienceHarbin Institute of TechnologyHarbin 150001People’s Republic of China Key Laboratory of Materials Modiﬁcation by Laser Ion and Electron Beams(Ministry of Education)School of PhysicsDalian University of TechnologyDalian 116024People’s Republic of China Center for Fusion Science of Southwestern Institute of Physics Chengdu 610041People’s Republic of China Shaanxi Key Laboratory of Plasma Physics and Applied Technology Xi’an 710100People’s Republic of China Xi’an Aerospace Propulsion Institute Xi’an 710100People’s Republic of China

Helicon wave plasma sources have the well-known advantages of high efficiency and high plasma density, with broad applications in many areas. The crucial mechanism lies with mode transitions, which has been an outstanding issue for years. We have built a fluid simulation model and further developed the Peking University Helicon Discharge code. The mode transitions, also known as density jumps, of a single-loop antenna discharge are reproduced in simulations for the first time. It is found that large-amplitude standing helicon waves(SHWs) are responsible for the mode transitions, similar to those of a resonant cavity for laser *** paper intends to give a complete and quantitative SHW resonance theory to explain the relationship of the mode transitions and the SHWs. The SHW resonance theory reasonably explains several key questions in helicon plasmas, such as mode transition and efficient power absorption, and helps to improve future plasma generation methods.

关键词： helicon plasma mode transition standing wave resonance

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电动汽车横摆力矩拉盖尔函数模型预测控制

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重庆大学学报（自然科学版） 2018年第1期41卷 61-69页

作者：吴明阳冀杰西南大学工程技术学院重庆400716

针对后轮轮毂电机驱动电动汽车横向稳定性的控制问题,建立了分层控制结构。上层控制器基于拉盖尔函数模型预测控制理论,跟踪理想横摆角速度,同时考虑附加横摆力矩约束,得出附加横摆力矩需求;下层控制器以后轮轮胎利用率为目标函数,考虑... 详细信息

针对后轮轮毂电机驱动电动汽车横向稳定性的控制问题,建立了分层控制结构。上层控制器基于拉盖尔函数模型预测控制理论,跟踪理想横摆角速度,同时考虑附加横摆力矩约束,得出附加横摆力矩需求;下层控制器以后轮轮胎利用率为目标函数,考虑轮胎附着约束和执行器约束,通过求解二次规划问题将附加横摆力矩分配到两个后轮。选取前轮转角阶跃输入和双移线2种工况,利用Carsim与Matlab/Simulink进行了联合仿真,仿真结果表明:在高附着路面条件下,所设计的控制方法减小了汽车瞬态响应的反应时间和超调量,提升了汽车瞬态响应的品质;在低附着路面条件下,所设计的控制方法使汽车能跟踪理想横摆角速度,避免汽车转向失稳。

关键词：后轮驱动模型预测控制拉盖尔函数控制分配电动汽车

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政府数据开放安全影响因素互作用框架的元综合分析

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情报杂志 2024年第10期43卷 199-206,F0003页

作者：冉连吴铭洋西华大学法学与社会学学院成都610039

[研究目的]平衡政府数据开放与安全是数字政府建设的关键议题。分析政府数据开放安全影响因素及其互作用关系,以健全政府数据安全治理体系。[研究方法]采用元综合分析方法,基于国内外各主流数据库,运用ConQual批判评价工具,筛选出34份... 详细信息

[研究目的]平衡政府数据开放与安全是数字政府建设的关键议题。分析政府数据开放安全影响因素及其互作用关系,以健全政府数据安全治理体系。[研究方法]采用元综合分析方法,基于国内外各主流数据库,运用ConQual批判评价工具,筛选出34份国内外政府数据开放安全有关质性研究样本,对筛选的文献进行解释性三级编码和综合归纳,构建政府数据开放安全影响因素互作用的综合阐释框架,并梳理各维度的交互关系。[研究结论]研究得到23个范畴、11个主范畴和4个维度,将其归纳为主体因素、文化因素、管理因素及资源因素4个维度组成的PCMR模型,将政府数据开放安全影响因素诠释为一个多主体、多要素共同作用的动态复杂系统,为后续政府数据开放安全治理的相关研究提供了重要的理论框架参考。

关键词：政府数据政府数据开放数据安全数据治理元综合分析法

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成都市降雨量及降雨侵蚀力年内分布特征研究

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人民长江 2019年第4期50卷 81-85页

作者：吴明洋重庆水利电力职业技术学院重庆402160

根据成都市1991～2010年逐日降雨数据,分析降雨量和降雨侵蚀力的分布特征。结果表明:成都市多年平均降雨量先增大再减小,8月份降雨量为245.79 mm,占全年降雨量的27.76%。7,8月份侵蚀性降雨量为169.4 mm和211.4 mm,分别占多年平均降雨量... 详细信息

根据成都市1991～2010年逐日降雨数据,分析降雨量和降雨侵蚀力的分布特征。结果表明:成都市多年平均降雨量先增大再减小,8月份降雨量为245.79 mm,占全年降雨量的27.76%。7,8月份侵蚀性降雨量为169.4 mm和211.4 mm,分别占多年平均降雨量的19.14%和23.89%,发生侵蚀性降雨天数为7.8 d和5.1 d。成都市多年平均降雨侵蚀力年内分布呈单峰式分布型,多年平均降雨侵蚀力为2 921.57 MJ·mm/(hm^2·h),7,8月份为1 000.65 MJ·mm/(hm^2·h)和1 008.97 MJ·mm/(hm^2·h)。降雨侵蚀力具有明显的季节性分布特征,春季、夏季、秋季、冬季的降雨侵蚀力分别为262.85,2297.46,350.06,11.2 MJ·mm/(hm^2·h),夏季占全年的78.64%。降雨侵蚀力与侵蚀性降雨量的相关性优于降雨侵蚀力与降雨量的相关性。研究结果可为成都市土壤侵蚀预报与评价提供科学依据。

关键词：降雨侵蚀力降雨量侵蚀性降雨季节分布成都市

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100t LF Si-Ca脱氧低铝锅炉管用钢15CrMoG夹杂物分析

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特殊钢 2018年第1期39卷 65-67页

作者：吴明洋山东钢铁股份有限公司莱芜分公司特钢事业部莱芜271105

高压锅炉管用钢15CrMoG(/%:0.12~0.18C,0.17~0.35Si,0.40~0.70Mn,≤0.015P,≤0.015S,0.80~1.10Cr,0.40~0.55Mo,≤0.020Alt)的生产工艺流程为60%铁水+优质废钢-100 t UHP EAF-LF-VD-Φ500mm坯连铸-轧制。通过电弧炉出钢Al-Si预脱氧,LF精炼Si-Ca脱氧,优化精炼渣系的组成为(/%):55~60CaO,30~35Al_2O_3,5~10SiO_2,(CaO)/(Al_2O_3)=1.41~1.74,精炼后钢水中的Alt为0.011%~0.014%。Φ140 mm和Φ160 mm热轧材的夹杂物分析结果表明,钢中夹杂物中MnS为10%,铝酸钙为75%,SiO_2 7.5%,含Ti氧化物5%,其它2.5%,钢中≤5.0μm夹杂物占95%以上,满足锅炉管用钢15CrMoG的技术要求。

关键词：高压锅炉管用钢15CrMoG EAF—LF—VD-Ф500 mm坯连铸低铝Si—Ca脱氧夹杂物

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